scholarly journals Identification of root-knot nematode species occurring on tomatoes in Kenya: use of isozyme phenotypes and PCR-RFLP

2012 ◽  
Vol 32 (02) ◽  
pp. 78-84 ◽  
Author(s):  
Rael Birithia ◽  
Wanjohi Waceke ◽  
Peter Lomo ◽  
Daniel Masiga
Keyword(s):  
Nematode Species ◽  
Root Knot Nematode ◽  
Pcr Rflp

Meloidogyne lopezi n. sp. (Nematoda: Meloidogynidae), a new root-knot nematode associated with coffee (Coffea arabica L.) in Costa Rica, its diagnosis and phylogenetic relationship with other coffee-parasitising Meloidogyne species

Nematology ◽  
2014 ◽  
Vol 16 (6) ◽  
pp. 643-661 ◽  
Author(s):  
Danny A. Humphreys-Pereira ◽  
Danny A. Humphreys-Pereira ◽  
Lorena Flores-Chaves ◽  
Danny A. Humphreys-Pereira ◽  
Lorena Flores-Chaves ◽  
...  
Keyword(s):  
Costa Rica ◽  
16S Rrna ◽  
Coffea Arabica ◽  
Phylogenetic Analyses ◽  
Mitochondrial Gene ◽  
Restriction Enzymes ◽  
Nematode Species ◽  
Male Body ◽  
Root Knot Nematode ◽  
Pcr Rflp

Coffee (Coffea arabica L. cv. Catuai) seedlings with abundant small root galls caused by an unknown root-knot nematode were found in southern Costa Rica. Morphology, esterase and malate dehydrogenase isozyme phenotypes and DNA markers differentiated this nematode from known Meloidogyne spp. A new species, M. lopezi n. sp., with common name Costa Rican root-knot nematode, is suggested. Meloidogyne lopezi n. sp. is distinguished from other coffee-associated Meloidogyne spp. by size of female lips and stylet, male body length and stylet and second-stage juvenile body and tail morphology. The region of the mitochondrial genome between COII and 16S rRNA showed a unique amplicon size of 1370 bp, and digestions with restriction enzymes HinfI, AluI, DraI and DraIII revealed characteristic PCR-RFLP patterns that differed from the tropical root-knot nematode species M. arabicida, M. incognita, M. izalcoensis, M. javanica and M. paranaensis. Characterisation of the protein-coding map-1 gene and phylogenetic analyses suggested that M. lopezi n. sp. might reproduce by mitotic parthenogenesis. Phylogenies estimated using Bayesian analyses based on the region between the COII and 16S rRNA mitochondrial genes, as well as the 18S and 28S ribosomal nuclear genes, indicated that M. lopezi n. sp. is closely related to other tropical Meloidogyne spp. that infect coffee, especially M. arabicida, M. izalcoensis and M. paranaensis from Central and South America. Isozyme analyses and PCR-RFLP of the COII-16S rRNA mitochondrial gene region enable a clear diagnostic differentiation between these species.

scholarly journals Histological Characterization of Resistance to Different Root-Knot Nematode Species Related to Phenolics Accumulation in Capsicum annuum

2005 ◽  
Vol 95 (2) ◽  
pp. 158-165 ◽  
Author(s):  
A. Pegard ◽  
G. Brizzard ◽  
A. Fazari ◽  
O. Soucaze ◽  
P. Abad ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Capsicum Annuum ◽  
High Performance ◽  
Nematode Species ◽  
Susceptible Cultivar ◽  
Resistant Line ◽  
Root Knot Nematode ◽  
Resistance Response ◽  
Root Knot Nematodes ◽  
Chromatography Analysis

In the pepper Capsicum annuum CM334, which is used by breeders as a source of resistance to Phytophthora spp. and potyviruses, a resistance gene entirely suppresses reproduction of the root-knot nematode (Meloidogyne spp.). The current study compared the histological responses of this resistant line and a susceptible cultivar to infection with the three most damaging root-knot nematodes: M. arenaria, M. incognita, or M. javanica. Resistance of CM334 to root-knot nematodes was associated with unidentified factors that limited nematode penetration and with post-penetration biochemical responses, including the hypersensitive response, which apparently blocked nematode migration and thereby prevented juvenile development and reproduction. High-performance liquid chromatography analysis suggested that phenolic compounds, especially chlorogenic acid, may be involved in CM334 resistance. The response to infection in the resistant line varied with root-knot nematode species and was correlated with nematode behavior and pathogenicity in the susceptible cultivar: nematode species that quickly reached the vascular cylinder and initiated feeding sites in the susceptible cultivar were quickly recognized in CM334 and stopped in the epidermis or cortex. After comparing our data with those from other resistant pepper lines, we suggest that timing of the resistance response and the mechanism of resistance vary with plant genotype, resistance gene, and root-knot nematode species.

Host suitability of summer cover crops to Meloidogyne arenaria, M. enterolobii, M. incognita and M. javanica

Nematology ◽  
2021 ◽  
pp. 1-9
Author(s):  
Hung X. Bui ◽  
Johan A. Desaeger
Keyword(s):  
Cover Crops ◽  
Nematode Species ◽  
Host Suitability ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Root Knot Nematode ◽  
Sunn Hemp ◽  
Host Status ◽  
Susceptible Control ◽  
Sorghum Sudangrass

Summary Cover crops can be a useful tool for managing plant-parasitic nematodes provided they are poor or non-hosts for the target nematode species. A glasshouse experiment was done to determine the host status of four common cover crops in Florida, sunn hemp, cowpea, sorghum sudangrass and sunflower, to pure populations of four common tropical root-knot nematode (RKN) species Meloidogyne javanica (Mj), M. incognita (Mi), M. enterolobii (Me) and M. arenaria (Ma). Tomato was included as a susceptible control. Eight weeks after nematode inoculation (WAI), tomato showed the highest root gall damage for all tested RKN species, with gall indices (GI) between 7 (Ma) and 8.5 (Me) and reproduction factor (RF) ranging from 20 (Ma) to 50 (Mj). No visible root galls were observed for any of the RKN species on sunn hemp and sorghum sudangrass at 8 WAI. However, Mj and Mi were able to reproduce slightly on sorghum sudangrass (RF = 0.02 and 0.79, respectively). Sunflower and cowpea were infected by all four tested RKN species, but host suitability varied. Sunflower root galling ranged from 1.1 (Me) to 4.5 (Mj) and RF = 3.2 (Me) to 28.7 (Mj), while cowpea root galling ranged from 0.6 (Mi) to 5.1 (Me) and RF = 0.8 (Mi) to 67.3 (Mj). Sunn hemp and, to a lesser extent, sorghum sudangrass were poor hosts to all four tested RKN species. Sunflower was a good host to all RKN species, but root gall damage and RF were lowest for Me. Cowpea was a good host to Mj, Me and Ma, but a poor host to Mi. Our results confirm and stress the importance of RKN species identification when selecting cover crops as an RKN management strategy.

Single pass cDNA sequencing - a powerful tool to analyse gene expression in preparasitic juveniles of the southern root-knot nematode Meloidogyne incognita

Nematology ◽  
2001 ◽  
Vol 3 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Jaap Bakker ◽  
Fred Gommers ◽  
Geert Smant ◽  
Pierre Abad ◽  
Marie-Noëlle Rosso ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cdna Library ◽  
Meloidogyne Incognita ◽  
Sequence Data ◽  
Homo Sapiens ◽  
Large Fraction ◽  
Nematode Species ◽  
Cdna Libraries ◽  
Parasitic Nematodes ◽  
Root Knot Nematode

AbstractExpressed sequence tags (EST) have been widely used to assist in gene discovery in various organisms (e.g., Arabidopsis thaliana, Caenorhabditis elegans, Mus musculus, and Homo sapiens). In this paper we describe an EST project, which aims to investigate gene expression in Meloidogyne incognita at the onset of parasitism. Approximately 1000 5′-end sequence tags were produced from a cDNA library made of freshly hatched preparasitic second stage juveniles (J2). The EST were identified in the primary transformants of the cDNA library, and assigned to nine different functional groups, including (candidate) parasitism genes. A large fraction of the EST (45%) did not have a putative homologue in public databases. Sixty five percent of the EST that could be clustered into a functional group had putative homologues in other nematode species. EST were found for virtually all parasitism related genes that have been cloned from M. incognita to date. In addition, several novel genes were tagged, including a xylanase and a chitinase gene. The efficiency of EST projects, which produce sequence data for thousands of genes in months time without any difficult pre-selections of mRNA pools, makes random sequencing cDNA libraries a superior method to identify candidates for parasitism related genes in plant-parasitic nematodes. The sequences in this paper are retrievable from Genbank with the accession numbers BE191640 to BE191741, BE217592 to BE217720, BE225324 to BE225598, BE238852 to BE239221, and BE240829 to BE240865.

scholarly journals Host Status of Lisianthus `Mariachi Lime Green' for Three Species of Root-knot Nematodes

HortScience ◽  
2004 ◽  
Vol 39 (1) ◽  
pp. 120-123 ◽  
Author(s):  
Martin Schochow ◽  
Steven A. Tjosvold ◽  
Antoon T. Ploeg
Keyword(s):  
Nematode Species ◽  
Meloidogyne Hapla ◽  
Cut Flower ◽  
Root Knot Nematode ◽  
Eustoma Grandiflorum ◽  
Root Knot Nematodes ◽  
Tomato Plants ◽  
Flower Production ◽  
Significant Damage ◽  
Host Status

Lisianthus [Eustoma grandiflorum (Raf.) Shinn.] plants were grown in soil infested with increasing densities of Meloidogyne hapla Chitwood, M. incognita (Kofoid & White) Chitwood, or M. javanica (Treub) Chitwood, root-knot nematodes. Compared to tomato plants grown in soil with the same nematode numbers and species, lisianthus had less severe root symptoms, suffered less damage, and resulted in lower nematode multiplication rates. Lisianthus was a better host for M. javanica than for M. incognita, and a poor host for M. hapla. Lisianthus shoot weights were significantly reduced after inoculation with M. javanica or M. hapla, but not after M. incognita inoculation. The number of flowers produced per lisianthus plant was reduced by all three nematode species. The results show that the root-knot nematode species that are most common in California may cause significant damage in the cut-flower production of lisianthus.

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